The quality of a commercial typical toothbrush depends on the quality of toothbrush bristles. The toothbrush bristles have been developed and used in various types according to shapes or material quality. For example, synthetic resins are normally used as the material for the toothbrush bristles. The main reasons are its good moldability in manufacturing and cheap manufacturing costs.
In addition to good moldability, the toothbrush bristles must be as soft as not to damage teeth or gum, and must be hard enough in durability. At present, PBT (Poly Buthyle Telephthalate) is widely used as the material for toothbrush bristles, because PBT has softness close to artificial fur, good moldability, good hardness, and so on, many advantages suitable to be in use for toothbrush bristles.
However, the typical toothbrush is not as useful as to clean and remove food particles and dental plague off from teeth and interdental portions because of various reasons, firstly wrong usage habits of toothbrush (left-to-right direction) by a user, and clean only front surface of teeth, furthermore too much pressure applied on the teeth causing tooth wear or gum damage and disease. Therefore, typical toothbrush has many disadvantages.
Because of the problems as above, the way of using toothbrush bristles by rotary brushing that is, the way of brushing like move of making circles may be used by a user. In the rotary brushing usage, a user pushes and fits toothbrush bristles into between teeth and gum and pulls the toothbrush bristles down to up in rotary brushing way, by which a user can remove food particles and dental plague better without much power and pressure.
However, the above rotary brushing usage also has many problems as below. When toothbrush bristles are pushed and fit into between teeth and gum in order to remove interdental foreign substances, the removal of the interdental foreign substances such as food particles and dental plague is not easy because of the structural defects of typical toothbrush (repulsive force of toothbrush bristles positioned in the middle). So, a user has to apply too much power and pressure on teeth and gum when brushing with the toothbrush so as to make brushing much difficult and result the toothbrush bristles bent and widen easily, and thereby the toothbrush cannot be used as long as much.
Secondly, since excessive power more than necessary to remove interdental foreign substances is applied to teeth and gum, the interdental foreign substances can be removed, but the teeth and gum may be damaged.
Thirdly, the foreign substances taken off from teeth and fit into the toothbrush bristles cannot be removed completely even though washing the toothbrush cleanly, since the typical toothbrush bristles are provided on the surface of the toothbrush head very densely. Furthermore, the toothbrush is not dried well and cannot be kept in good condition so that bacteria is more easily produced causing infection in gum and various gum disease.
Fourthly, toothpaste more than necessary is put on toothbrush bristles and too much amount of toothpaste is used inside mouth since the toothbrush bristles are formed very densely, which is the problem of inefficient use and waste of toothpaste.